Who is to blame for indecent dressing in society today?

The blame falls to the same as every other problem in society: parents, individuals, and the members of society as a whole. They way people dress is a personal decision. How that person is greeted by society is a societal decision. What that person does until he or she reaches the age of adulthood is the fault of the parent, and even afterward some of the responsibility is still that of the parent.